A Santa Monica, Calif., judge granted the political and social activist's petition for a gender and name change Thursday, according to a spokesperson for the Transgender Law Center, which represented Bono.

"Chaz couldn't be happier," says Kristina Wertz, legal director for the Transgender Law Center. "This is an important step in his transition and will allow him to change a variety of his identity documents to show who he truly is."

Born Chastity Bono to famous parents Cher and Sonny Bono, Chaz started the female-to-male sex change March 2009, shortly after his 40th birthday.

"It's hard for me to articulate how this feels – when you've lived your whole life in a body and having everybody relate to you as something you don't feel," Bono, 41, told PEOPLE back in December. "When that finally gets righted, it's just amazing. I finally get to live my life the way I've always wanted to."